NET::ERR_CERT_DATE_INVALID means the dates do not add up. Every HTTPS site has a security certificate that is valid between two dates. Chrome compares those dates with your device's clock. If today, according to your device, falls outside that window, Chrome stops and shows a warning.
There are two possible reasons, and Chrome shows a different page for each. Either your device's date and time are wrong, in which case the heading is Your clock is ahead or Your clock is behind. Or the website has let its certificate expire, in which case the heading is Your connection is not private with this code underneath.
Which is it: your clock or the website?
- "Your clock is ahead" or "Your clock is behind". Chrome has already decided the clock is the problem. The page says a private connection can't be established because your computer's date and time are incorrect, and shows the date it thinks your device is set to.
- "Your connection is not private". Select Advanced. Chrome tells you how many days ago the certificate expired and what your clock is currently set to, and asks whether that looks right. If the date shown is correct, the site's certificate has expired.
- Every secure site shows the warning. It is your device. One website cannot break all the others.
- Only one site shows it, on every device. It is the website. Our website checker shows whether the site is responding at all.
Fix your device's date and time
- Windows 11. Go to Settings, Time & language, Date & time. Turn on Set time automatically, check the time zone, then select Sync now.
- Mac. Open System Settings, General, Date & Time and turn on Set time and date automatically.
- iPhone and iPad. Go to Settings, General, Date & Time and turn on Set Automatically.
- Android. Open Settings and search for "date". Turn on automatic date and time, and automatic time zone.
- Check the year as well as the time. A clock that shows the right hour in the wrong year is a common cause.
- Reload the page. Chrome's clock page also has an Update date and time button on some devices that takes you straight to the setting.
If the clock is right and the warning stays
- Try the site on another device or on mobile data. If it fails there too, the certificate has expired and only the site owner can renew it.
- Update your browser and operating system. Chrome's help page lists this for certificate errors, because updates refresh the list of certificate authorities your device trusts.
- On public Wi-Fi, sign in to the network first. Hotel and café networks intercept pages until you have accepted their terms.
- Pause HTTPS scanning in your antivirus to test, then turn it back on. Chrome's help page names this as a cause of certificate errors.
Should you click "Proceed"?
Under Advanced, Chrome may offer a link to proceed to the site, marked (unsafe). Do not use it on any site where you sign in, pay, or enter personal details. An expired certificate on a small hobby site is usually an oversight, but your browser can no longer confirm who is on the other end, and neither can you. If a bank, email or shopping site shows this warning, close the tab and try again later from a network you trust.
The clock keeps resetting
If you correct the date and it is wrong again the next time you switch on, the device is losing track of time while it is off. Desktop PCs and many laptops keep the clock running with a small coin-shaped battery on the motherboard, often called the CMOS battery. When it runs flat, the PC starts up with a date years in the past, and every secure website fails until Windows syncs the time again. Replacing that battery is the lasting fix. Until then, Sync now in the Windows date and time settings gets you going after each start.
A wrong time zone causes smaller errors, usually of an hour or more. That is enough to break sign-ins on some sites even when certificate checks pass, so set the time zone automatically too.
Old phones, tablets and computers
A device that no longer receives updates can show date-related certificate warnings even when its clock is right. Every device carries a built-in list of trusted root certificates, and those roots have expiry dates of their own. When a widely used root run by IdenTrust expired on 30 September 2021, sites using free Let's Encrypt certificates started showing warnings on older devices. Let's Encrypt said Android versions before 7.1.1 were affected. The fix on such devices is a system update if one exists, or a browser that carries its own certificate list, such as Firefox.
Chrome's help page also lists one Mac-only cause: an expired DigiCert root certificate stored in Keychain Access, which can be shown with the option to display expired certificates and then deleted.
If it is your website
Check the expiry date of the certificate the server is actually sending, not just the one you think you installed. Renew it, install the full chain, and restart the web server so the new file is loaded. A certificate that was issued minutes ago can also fail for visitors whose clocks run slightly behind, because to them it is not valid yet. Chrome words that case as a certificate that is "supposedly from" the future. Automatic renewal avoids most of this.
Related fix guides
Questions
Why does Chrome say my clock is ahead?
Your device's date or time is set later than the real time, so certificates look as if they are not valid yet or have already expired. Turn on automatic date and time in your device settings and reload the page.
Is NET::ERR_CERT_DATE_INVALID my fault or the website's?
It can be either. If it appears on every secure site, your device's clock is wrong. If it appears on one site on every device, that site's certificate has expired and the owner has to renew it.
Why do I get NET::ERR_CERT_DATE_INVALID on every website?
Your device's date, time or year is wrong, so every certificate looks out of date. Set the date and time to automatic. If the date resets each time you start the computer, the clock battery on the motherboard probably needs replacing.